This invention relates generally to the field of vision testing and more specifically to a machine for measuring glare in two modes, macular photostress, and blue field entopic phenomenon. Glare testing is well established for evaluating abnormal conditions of the human eye that cause undue scattering of light and visual disability. Disabling glare originates from two lighting modes, diffuse (flood) lighting and focal (spot) lighting. An example of flood lighting is sunlight brightly shining through a picture window and the best example of spot lighting is glaring headlights of oncoming vehicles. Medicare ruling recognizes the impairment and dangers of glare by providing re-imbursements for cataract surgery when visual acuity is less impaired than the visual requirement when glare is not a factor. Glare testing attempts to mimic environmental lighting conditions to demonstrate and document the disability of glare.
The most commonly used glare tester is the flood lighting producing hand-held Brightness Acuity Meter (U.S. Pat. No. 4,784,483). Similar in principle to the Brightness Acuity Meter is the Glare Test Attachment described in U.S. Pat. No. 6,783,239B2, which fits onto an existing illuminating, source, such as, an ophthalmoscope or transilluminator. An example of a spot lighting source glare tester is the AC powered CSV-1OOOHGT (Halogen Glare Test, marketed by Vector Vision, Greenville Ohio) where glare producing spot lights aligning towards the subject are mounted on the sides of the vision chart.
My inventions improves flood lighting producing glare testing by providing a smaller and lower weight instrument for compact assembly without compromising brightness by utilizes a mirrored surface to intensify the light from a low energy LED battery powered light bulb. Another embodiment of my inventions provides for the first time the positioning of glare producing spot lights within the line of sight and this advancement provides testing that closely duplicates approaching automobile headlights, the major environmental glare problem.
Macular photostress testing is a method of detecting diseases of the macular. After saturating the macula of the retina with bright light, there is a period before the function of the macula returns to normal and full vision returns. This refractory period is prolonged in certain diseases of the macula. My invention provides as multifunction device to test photostress and other eye functions
The blue-field entopic phenomenon flying corpuscles is elicited by exposing the eye to light in the 425 to 450 nm wavelength range. Under correct conditions of blue light illumination, normal sighted subjects see an entopic phenomenon of tiny light colored darting images in their central field of vision. It is believed that the tiny moving images represent white blood cells circulating through the retinal blood vessels. The absence or a sparsity of this phenomenon is a sign of disease. My invention provides the correct setting for this phenomenon as well as glare testing and photostress testing.